Mechanisms determining ozone abundance
The link between ozone and the halogenated substances destroying it is complex: their distribution and evolution in the stratosphere are determined by a succession of chemical and physical mechanisms, even depending on the meteorology.
To understand them, a global and regular cartography of the different atmospheric constituents, like NO2, BrO, aerosols and OCIO, is required.
The GOME satellite and its successors have mapped, on a continuous basis, the integrated column of these constituents since 1995. But their ability to measure the vertical distribution is very limited. And most of all, they cannot take measures in the polar night darkness. Yet, it is precisely during this period that the vortex is developing above the pole. The vortex is where the mechanisms that would lead to the formation of polar ozone holes in spring will set off.
By observing the stars through the atmosphere, the GOMOS instrument onboard the ENVISAT satellite is able to map stratospheric ozone all around the globe, including during polar night, and in only three days. GOMOS also detects other constituents involved in ozone chemistry, like:
BIRA-IASB was assigned by ESA as expert laboratory to design and develop the algorithms of GOMOS. In order to anticipate the needs of remote sensing for the ozone layer monitoring for the next decade, BIRA-IASB is now developing the ALTIUS project, which will be the first Belgian observation mission of the stratosphere from a PROBA microsatellite.